Rollerball contacts?

[thatman]

I'm considering using rollerball contacts for my windows.

Since I'd like to be able to open them a few inches at night as a vent, installing them a few inches from the closed-edge of the frame (they slide sideways), they seem like a great thing to use.

Anyone have experience with the Ademco 956RPT?

 

[jpmargis]

I'm considering using rollerball contacts for my windows.

This is a very bad idea. Pretend you are a sophisticated burglar and you will see why. Also, they have a potential "stuck closed" failure mode.

Please consider magnetic contacts with two magnets to achieve your goal.

 

[tmbrown97]

:hesaid:

I don't have a lot of experience with different window types - out here is all relatively new construction and the only thing that's changed is going from metal frames to vinyl... but the windows I've seen usually have a channel on the edges that would make it so the roller usually wouldn't get pressed in enough.

I haven't seen anyone do this in practice in probably 20 years (at least first hand) but I remember a long time ago, the high-end security guys would do two magnets (as mentioned above) - one in the fully closed position and one open 3-6". There would be a subtle line on the window that, if opened to that point, you'd engage the second magnet allowing you to arm the alarm. If anyone tried to touch the window to open it further, off the alarm would go.

I suspect there aren't many custom alarms anymore - unfortunately the majority are trunk-slammer adt/bay alarm/etc contractors basically so people are stuck bypassing open windows.

Security screens are another great option - you get an alarm trigger when the screen is cut or removed before the person has even gotten to the window.

 

[apostolakisl]

Double magnets is how I did it.

 

[Del91574]

This is a very bad idea. Pretend you are a sophisticated burglar and you will see why. Also, they have a potential "stuck closed" failure mode.

Please consider magnetic contacts with two magnets to achieve your goal.

While most modern rollers or plungers have a magnetic reed, they're still operated by physical means (the plunger etc.) and the springs inside will corrode and stick when mounted in a windowsill...notice I said will, not IF, it's an inevitable event, so now the contact will not actuate because the plunger is physically bound up.

In the case of wanting to leave a window open, there's a couple of options, some are better than others. I have seen people parallel a surface contact with a recessed contact on a window. While it will work, it's a bad idea to parallel any devices on a protective circuit. The more common ways are to either install surface contacts and 2 magnets (with the second "flipped" 180* from the other so the magnet poles go N-S S-N, otherwise you created a huge security flaw in how the contacts work, especially if wide gap magnets are installed). The other option is security screens or GRI makes a "vent switch" that allows 6 or 8" of linear travel on the sash itself.

The easiest option, if asthetics are paramount would be to design the system appropriately and bypass the windows within the occupied area, however that does negate the protection factor.

 

[Neurorad]

That GRI vent switch is a nifty idea.